The interior of an aircraft is subject to special requirements. A modular construction is frequently desirable to accelerate the final assembly through the installation of subassemblies and to simplify future maintenance. For precise adaptation, it must be possible to compensate tolerances, possibly during the final assembly. Undesired assembly positioning can occur, for example, when a module has to be fitted into a recess although a visible surface of the module does not terminate flush with adjoining edges of the recess.
Furthermore, the modules can include heavy supply units, such as those used for example for air conditioning or water supply and disposal on long haul flights. The fastening device has to be able to transfer the inertia forces of the heavy module to the aircraft structure, even in extreme situations such as a hard landing of the aircraft. If the fastening device were to break, for example in a hard landing, the risk of injury would be considerable owing to the proximity to passengers or the personnel using the module. For this reason, fastening devices for modules are designed, for example, to transfer forces of up to 10,000 N.
Even in a normal flying situation, the aircraft structure carrying a module is subject to vibrations caused by rotating engines and relatively minor air turbulences. Transferring these vibrations to the module can reduce its service life, thereby increasing the maintenance costs or even endangering flight safety.
The modules can contain electrical devices, in which case a potential equalization relative to the (electrical) ground of the aircraft is advantageous for their operational reliability. Modules which are not provided for electrical operation can also require a potential equalization. For example, as a result of the above-mentioned vibrations at material boundaries, it is possible for an electrostatic charge to build up which increases the risk of ignition, interferes with the functional capability of other devices or impairs the ease of use of the module.
A further feature is a simple foolproof operability of a fastening device for a module in an aircraft. For example, it may be necessary to replace the module outside regular maintenance intervals. In such a case, it would be advantageous for the fastening device to be operated preferably without tools and as quickly as possible, perhaps by the cabin crew.
The subsequently published document DE 10 2008 015 648 A1 describes a vacuum suction means for temporary fixing to a substantially smooth airtight fastening surface. The vacuum suction means can be used to lift objects whereby, to maintain the operational reliability, a vacuum display device can detect when a minimum negative pressure between a suction plate of the vacuum suction means and the fastening surface has not been reached. A negative pressure is built up as a result of changing the position of the suction plate in certain areas using a toggle lever or articulated lever.
The printed document DE 200 04 718 U1 discloses a push-in stud which is used to connect two components in through openings in the two components, which through openings are brought into congruence. By way of a toggle or articulated lever which is guided outwards, radially displaceably mounted latching means can be moved into a radially extending position.
Conventional fastening systems only fulfill the above-mentioned requirements in an aircraft to a limited extent. For example, existing fastening systems only transfer forces in individual directions, which is why a plurality of differently orientated attachments is required for each module. Although more complex fastening systems are capable of reducing the transfer of vibrations, they do not allow for assembly or disassembly without a special tool due to their complexity. Moreover, known fastening systems stipulate a potential equalization for individual components, which has to be connected to the ground of the aircraft in addition to the fastening system and therefore requires an additional assembly step.